Magnetic separator



May 2l, 1929. A, F, JOBKE 1,714,171

MAGNETIC sEPARAToR Filed Jan. l2, 1926 Patented May 2l, V1929.

OFFICE.

AUGUST I'. JOBKE, 0F PITTSBURGH, PENNSYLVANIA.

MAGNETIC SEPABATOR.

Application led January 12, 1926. Serial No. 80,745.

My invention relates to that type of magnetic separators, which is known as the drum type, consisting with axial cores and cir mainly of a magnet system cula'ror segmental poles extending in radial planes and a rotatable drum arranged outside of the magnet system co-axially with the same, to carry the material to be separated.

As used heretofore, the poles, arranged in `a radial plane,

which is also the plane in which the material to be treated travels, are

of a uniform radial 'length The intensity of the field bein polarity.

and alternating tween them, and extending through the sur'- rounding drum in an uniform drum at its top tangled in the mixture cannot `and the material charged o axial direction, is

is held by the lines o force the drum from the moment be removed by gravity, and it is only such parts which during a half revolution may have a, chance to slide out of the intermeshing magnetic parts and the free non-magnetic parts, which can be separated from the magnetic ones. Particles such as br ass chips and turnings, inter'- mingled with steel turnings do not all have the opportunity of being unliooked and will therefore not fully be separated from.

them. If the material to be separated consists of fine particles, netite and is char such as filings or magged in a thick layer, the

non-magnetic particles near the drum are held by the magnetic ones with a considerable force so that they cannot drop off as long as the field traversing them is uniform between poles.

This condition is just as if the drum were standing still.

In order to overcome the handicaps thus mentioned and to attain arrangements, which are enabled to separate materials of different and difficult characters, such as metal cut-- tings with ragged edges or magnetites of extremely ne distribution in rock which have to be crushed and ground to a very fine size,

my invention consists of improvements,

which will vary the relative position between the material and the field in direction and intensity,

ticles to shift or causing the magnetic par vary their position in angulardirections and agitate the non-magnetic parts so as to enable them to free themselves and drop off b efore the magnetic particles the i are out of the field, proved separation.

I attain these objects through the improved arrangements and combinations of parts described below and illustrated in the accompanying drawing, in which .similar reference characters refer toisiniilar parts in each view, of which:

Figure l is a section through a radial plane of a separator, showing magnet poles with individual pole projections;

Figure 2 is an axial section through the machine and part of' the magnet system, showing the displacement between pole projections of opposite polarity;

Figure 3 is a section similar to that shown in Figure 2, and may be viewed with reference to Figure l; it shows an additional improvement in the tilted arrangement of the poles relative to the axis of the machine.

Figure 4 shows a single magnet pole with hub, hforming the magnet-core, and cast pole projections according to my invention.

Figure 5 is a view of the magnet field resulting from the arrangement shown in Figure 3, developed into a plane.

Figure 6 is a fragniental axial section through two adjacent poles pieces and the drum, showing the approximate formation of the resultingdield in a radial direction.

"ie magnet""`system in Figures 1 and 2 consists of the segmental poles 11 and 12 of opposite polarities, the hubs 13 of which form the cores carrying the exciting coils 14. The shaft 15 is held immovably but adjustably in bearings 16. At the leads 17 the current for excitation is introduced, and the coils, as a rule, are connected in series, al-

thiis securing an imternately in opposite direction. On the shaft 15 the drum 18 of non-magnetic material rotates by means of the drum heads 19, and a pulley or gear 20 is provided as a means for rotating the drum. A chute or conveyer 21 transports the material to be separated to the drum.

Poles 11 and 12 are provided with polar projections 22 instead of a continuous circumference, and projections ofv adjacent poles are displaced one-half the pitch relative to each other, as indicated in Figure 1. A resulting developed top view would then show the polar projections arranged in a diamond shape similar' to Figure 5, but projections of the same pole would be parallel to the dotanddash line F-F, which is in the direction of the feed and travel of the material on the drum 18. The lines of force concentrate at the polar projections, leaving a weaker field between them, which can he predetermined in strength by the depth oiE the depressions between the projections, so that everywhere there is suiicient strength in the iield to hold the magnetic parts to the drum.

While in Figure 3 there are all the essential parts as shown in Figures 1 and 2, I have tilted the magnet poles 11\ and l2 a certain angle from the radial plane. While the field arrangement is in general the same, the polar projections 22 being staggered as shown in Figure 1, the developed field is now exactly as shown in Figure 5 with relaf tion to the travel of the material, which is indicated by the dot-and-dash line F-F. It must be stated here, that the field shown in Figure 5 is incomplete in so far as the lines of force extending from the faces of the polar projections outward as those extendlng from the faces of poles between projections are omitted. In fact, the field is entirely covered with lines of force, as a com arison with Figure 6 will disclose.

Tllie material is then subject to the following influences:

1. From the strong lines of force between polar projections of opposite polarity; they are shown in Figure 5 by the full diagonal lines 23 and cause the-magnetic particles to change their angular position on the drum continuously.

2. From the weaker lines of force between oles, shown in dotted lines 24, which vary rom the angles of the stronger lines to an axial direction midway between the projections of the same pole; they have a tendency to reduce the sliding ofthe material on the drum and assist in supporting the angular motion.

3. From the relative motion between the material and the polar projections due to the angular displacement of the poles; it will be necessary to view the plane of the field of Figure 5 in connection with Figure 6, where the extension of the magnet field betweeny poles is shown. The individual magnetic lines of force may be indicated by the dotted curves in Figure 6. Relative to the surface ofthe drum 18 they extend in various angles beyond the same, being steep above the pole-faces and inclined between them. Small particles, or such of only one major dimension, for instance chi s, tend to align themselves along the lines o force and form chains 26, and any axial movement relative to the poles will. place these chains into different lines of force, i. e., these chains of particles will change their angular position on the drum. This is accomplished through the angular arrangement of the poles as shown in Figure 5; a point on the drum, say, that which travels on the line F-F, will have a movement relative to the pole underneath, as if the pole itself were traveling from left to right. Consequently a chain of magnetic particles formi-ng a fiat angle to the right at entering the field will swing through `a right angle to a flat angle to the left before leaving the field. It is this movement which enables a nommagnetic particle, which at first has been entrained underneath, to be freed and fall off before the separation is completed.

For this reason, a field pole of uniform radial length, but inclined toward a radial plane, as shown in Figure 3, will form an improved separator and allow the material to be agitated successfully.

A Another useful combination 'of magnet iield consists of poles of uniform radial length substantially, alternating with poles having projections as in Figure l, and all inclined toward radial planes. Such an arrangement, due to the reduced reluctance, is stmnger magnetically than one using poles with polar projections only.

Figure 6 shows one more arrangement to improve the separation of magnetic material. On the drum there are indentations 25 shown, the purpose of which is to reduce the bunching of magnetic material above the poles. Individual particles, or chains of them 26, as referred to above, have the tendency to slide over a smooth drum to the densest lines of force at the magnet poles, and the spaces between the latter become voided. In roviding these indentations, which may e circumferential or axial grooves, or lentil shaped as produced with a round-nose tool, there is a stop provided, against which the particles 26 may slide and there swing angular-1y without sliding toward the poles. In keeping the mass distributed uniformly over the Surface of the drum, the disengagement of non-magnetic particles is considerably facilitated and the capacity of the machine increased.

While the poles as shown in Figure 3 are inclined toward radial planes throughout, necessitating a bore for the shaft 15 at the angle of inclination, Figure 4 shows a form of pole, which is symmetrical to the axis, but the polar projections are bent so as to follow the corresponding line of slant. Either form is operative, and the showing of both is for the purpose of avoiding limitations to constructional details.

Having thus described my invention, what I claim is.:

1. In a magnetic separator of' the drum type, a magnet system, having its cores arranged in an axial direction and its poles arranged in substantially radial planes and provided with polar projections 1n a radial direction at determined intervals, and mag- 3. In a magnetic separator of the drum type, a magnet system, having its cores in' an axial direction, and its oles arranged in planes at an angle to radia directions.

In a magnetic separator of the drum type, a magnet s stem, having its cores arranged in an axial direction, and its poles arranged in planes at an angle to radial directions and provided with polar projections at determined intervals.

5. In a magnetic separator of the drum type, a magnet system, having its cores arranged in an axial direction and its poles arranged in planes at an angle to radial directions and provided with polar projections at determined intervals,I the projections of adjacent poles being staggered relative to each other.

6. In a magnetic separator of the drum type, a magnet stem, having its cores arranged in an axial direction and its poles arranged in radial planes and provided with polarirojections at determined intervals arrang in planes at an angle to the radial planes. l

7. In a magnetic separator of the drum type, a magnet system, having its cores arranged in an axial direction and the poles arranged in radial planes and rovided with polar (projections at determine intervals arrange in plates at .an angle to the radial plane, the projections of ad'acent poles being staggered relative to eac other.

8. In a magnetic separator of the drum type, a magnet system with cores arranged in an axial direction and m et poles arranged in approximately rall planes, a non-magnetic rotatable drum surrounding the same and indentations in the outer surface of the drum adapted to prevent the sliding of magnetic particles toward-theJf-fpoles of the magnet system.

9. In a magnetic separator of the drum type, a magnet system with cores arranged in an axial direction and magnet poles arranged in approximately radial planes, a non-magnetic rotatable drum surrounding the same and indentations in the outer surface of the drum extending in a tan ential direction, adapted to prevent the sli ing of magnetic particles toward the poles of the mzgnet system.

n testimony of which I allx my signature.

AUGUST F. JoBKE. 

